The T140 is a super fishing platform. The T160/T160i is almost as nice for pure fishing. The T140 has a better deck in the cockpit for standing if you have good balance. The T160/T160i is superior for longer paddles due to being a tad longer, and the Greenland bow design.
Storage.......The tank well area of the T140 is better than the T160/T160i, it holds more which makes external storage a bit nicer. The T160/T160i has superior internal storage. I can fit a 12' surf rod inside the hull along with camping gear etc. etc. So that area is a trade off.
Manuverability..........The T140 can turn a bit quicker. The T160/T160i will require a couple extra strokes. Although I can turn my T160i......360 degrees in 4 strokes by using 2 forward and 2 back stokes alternately.
Cockpit...........T140 wins hands down, I personally think its a better cockpit for setting up to go fishing.
Stability...........both are about the same to me.
Rough water.....I can't speak for the T140 in rough seas. But the T160 handles most any condition pretty nicely. In confused water/shoals.......it handled very well. Some say the T140 is better in choppy water.........I dunno......so I wont say.
I tried a friends T140 and really liked it. I ended up buying the T160i because when I go fishing.........it usually turns into a mini exploration. I love checking out nooks and crannies...or just cruising along. The T160/T160i is superior to the T140 in that regard. It definately cruises better.
I personally believe I would have been extremely happy with either boat. But since buying my T160i, I'm sold on it. I'm not a kayak expert by any means. But I can relate my engineering background and small craft experince enough to know these boats are serious platforms that do what they were designed for very well.
I hope this helps you...............or did not confuse you.
V/R John